I've manually created a service user account on my machine, and I'm surprised to see it on the Unity login screen. I searched this site and I've seen people had problems with this, but in those cases, the UID was above
minimum-uid and the suggestion was to either change the uid or add the user to the
hidden-users list. But my case is different.
The user account in question is:
UID = 118; GID = 8 (mail)
/etc/lightdm/users.conf file is configured like this:
[UserAccounts] minimum-uid=500 hidden-users=nobody nobody4 noaccess hidden-shells=/bin/false /usr/sbin/nologin
In my understanding, since the UID is below 500, it must not show up on the login screen. But it does anyway. I also don't understand why all the other service accounts don't show up then - they aren't listed in
hidden-users either. I don't see the difference between my service account and all the others on the system.
Note that I have this service account for more than a year now, but it only showed up on the login screen after I upgraded to Saucy from Quantal. Before that, while I was using Quantal, it was correctly hidden.
Before using the
hidden-users hack, I'd like to understand why it works like this.